The present invention relates to a locking device for a sports footwear, the locking device being adapted to lock two mutually hinged portions of the footwear relative to each other or release them from each other. More particularly, the present invention relates to a locking device for a sports footwear comprising a shell and a cuff that are hinged to each other, the locking device being adapted to lock the shell and cuff to each other or release them from each other.
The present invention finds application, for example, in the field of ski boots, both ski-touring boots and alpine ski boots. The present invention further relates to a sports footwear provided with the aforesaid locking device.
Sports footwear comprising a substantially soft inner element and a substantially rigid outer element are known. A typical example of this kind of footwear consists of ski boots, which have a substantially soft inner liner and a substantially rigid outer shell.
According to prior art, in the ski boot a cuff adapted to receive the user's ankle and lower part of the leg is coupled to the substantially rigid shell configured for receiving the user's foot. The cuff is generally hinged to the shell at the malleolar region, so as to allow, if desired, a rotation of the cuff relative to the shell. More particularly, when the user is skiing, it is preferable that the cuff is locked relative to the shell, so that movements, even minimal ones, of the user's leg are rigidly transmitted to the ski boot and from this to the ski. Instead, when the user is not wearing his/her skis and has to walk, it is preferable that the cuff is free to rotate relative to the shell, so as to make walking more comfortable.
Devices that can move from a first configuration in which rotation of the cuff relative to the shell is locked (configuration suitable for skiing) to a second configuration in which the cuff can rotate relative to the shell (configuration suitable for walking) are known from prior art. More particularly, in the case of ski-touring boots, in the first configuration the locking devices of the aforementioned type are configured so as to lock the relative movement of the cuff relative to the shell in both directions, whereas in the case of alpine ski boots, such boots are configured so as to lock the relative movement of the cuff relative to the shell only in one direction (i.e. the direction in which the cuff rotates towards the shell).
Such locking devices generally provide for a male member connected to the cuff and a female member connected to the shell, or vice versa, at least one of the members being arranged movably. The male member can be brought, for instance by means of a rotational or translational movement, to engage into the female member or disengage therefrom, or vice versa; when the male and female members are mutually engaged, the rotation between shell and cuff is prevented, whereas when the male and female members are mutually disengaged the cuff is free to rotate relative to the shell. Actuating elements are provided for actuating the rotational or translational movement of the male member (or of the female member) for moving from a configuration to the other one.
In the most simple and widespread embodiment, the male member of the locking device comprises a body having one or more teeth and the female member comprises a body in which one or more corresponding seats for the teeth of the male member are provided.
The coupling between the male member and the female member necessarily requires some clearance between the two members, due on one part to the manufacturing tolerances and on the other part to the need of providing for a theoretical clearance intended to compensate for the rotational adaptation between shell and cuff. When a transverse translational adaptation between shell and cuff (“canting” adjustment) is to be taken into account, this clearance is very high.
The clearance between the aforesaid two members increases progressively during the use of the ski boot due to wear, with a speed that depends on the materials that are used and to the applied loads. The presence of such clearance between the two members of the locking device is a remarkable drawback for the user, because even in the locked position (configuration suitable for skiing) some relative movement between shell and cuff of the ski boot still exists.
This drawback is particularly detrimental when taking into account the fact that the locking device is positioned in the lower part of the cuff, in the vicinity of the hinge point of the cuff to the hull; a clearance, even a small one, in such a position results in a perceivable rotation of the cuff in its upper part; for example a clearance of 0.5 mm between the members of the locking device can result in a relative movement of the top of the cuff up to about 4-5 mm, distinctly and unpleasantly perceivable by the skier.
The object of the present invention is to solve the above mentioned problem by providing a locking device able to effectively lock the cuff and the shell of a ski boot relative to one another. This and other objects are achieved with the locking device and the sports footwear as claimed in the appended claims.